The absorption and metabolism of each form of vitamin B6 by the perfused liver, kidney, skeletal muscle and intestine of the rat will be studied using tritium labeled vitamers. Established methods of separating the metabolites will be used. The primary concern will be the identification of the major forms of vitamin B6 which are taken up and exported by each of the perfused organs. Such data will be necessary to an understanding of the whole body utilization of vitamin B6. Similar work with niacin and niacinamide will be continued to ascertain the function of these two compounds in the metabolism of pyridine nucleotides.